Advances in poultry embryology have made possible the addition of various substances to the embryo or to the environment around the embryo within an avian egg for the purpose of encouraging beneficial effects in the subsequently hatched chick. Such beneficial effects include increased growth, prevention of disease, increasing the percentage hatch of multiple incubated eggs, and otherwise improving physical characteristics of hatched poultry. Additionally, certain types of vaccinations which could previously only be carried out upon either recently hatched or fully mature poultry can now be successful in the embryonated chick. In ovo administration techniques that replace the injection of very young hatched chicks can increase the efficiency of administration and reduce the stress on young chicks caused by injection.
Many methods of adding compounds to avian eggs utilize the injection of fluids by syringe. One traditional method has been syringe injection of eggs by hand. A number of automatic egg injection devices have also been developed. These include U.S. Pat. Nos. 5,056,464 to Lewis; 4,903,635 and 4,681,063 to Hebrank; 3,377,989 to Sandhage; and 4,040,388, 4,469,047, and 4,593,646 to Miller. A review of all these patents and their associated systems reveals, however, that all require that fluid be delivered from a storage device to the egg through a system of pumps and tubing which carries the fluid to the syringe needle.
Several injection devices seal the injection site after injection to prevent leakage and contamination. U.S. Pat. No. 4,040,388 to Miller describes heating the portion of the injection device which punctures the egg, allegedly sterilizing the exterior of the egg and also sealing the hole by heat coagulating a small portion of the egg albumin. U.S. Pat. No. 4,593,646 to Miller et al. discloses sealing of eggs after injection by heating and coagulating the albumin located near the injection site. An additional sealant is then applied to the outer shell by dipping each egg in a bath of sealant. U.S. Pat. No. 2,477,752 to Kiss discloses a method of injecting fertile eggs for the purpose of producing chicks have colored down. The '752 patent describes manual injection of the egg and subsequent sealing of the injection site.
Methods other than syringe injection to add compounds to eggs have been disclosed. U.S. Pat. No. 3,256,856 to Nicely discloses puncturing the egg shell over the air cell, applying negative pressure to draw air from the air cell, and then immersing the egg in a bath of liquid treatment material and returning to atmospheric pressure to draw treatment fluid into the egg. Treatment substances have also been administered by creating a pressure gradient across the shell or by immersion in a treatment bath. See also U.S. Pat. No. 4,928,628 to Gassman, 4,928,629 to Trampel, and 2,734,482 to Seltzer. These techniques are generally cumbersome and difficult to apply on a commercial scale.
For some applications it would be desirable to have a means for delivering substances into an egg other than by automated syringe injection. Other than hand injection with a syringe, however, few such techniques are available.
In view of the foregoing, an object of the present invention is to provide methods and apparatuses for in ovo injection in which injection and sealing of the injection site is accomplished in one step.